Immunization is the process of administering antigenic material (e.g., a vaccine) to produce or artificially increase an immune response. One frequently encountered problem is that many antigens used for immunization are not sufficiently immunogenic to raise an antibody titer sufficient to provide protection against future challenge. Weak antigens may also be deficient in inducing cell-mediated immunity.
To strengthen the humoral and/or cellular immune response to an antigen, it is common to administer an antigen in conjunction with an adjuvant. An adjuvant is a substance that enhances the immune response to an antigen. Administration of an adjuvant with an antigen may cause an individual to respond to an antigen who otherwise would not respond in the absence of the adjuvant. Commonly used adjuvants include Freund's adjuvant, Keyhole Limpet Hemocyanin (KLH), and granulocyte-macrophage colony stimulating factor (GM-CSF). Despite the immune-enhancing properties of known adjuvants, these adjuvants remain insufficient to induce an immune response in a subject against many clinically important antigens, for example, tumor associated antigens.
Accordingly, there is a need for new adjuvant compositions.